1. Field of the Invention
The invention is concerned with a device constructed as a self-propelled steerable vehicle for one person, who would normally be invalided by a leg and/or hip condition, the driver's seat of which may be a wheelchair. More particularly, the invention relates to a vehicle whereby the aforementioned wheelchair may be driven onto the vehicle's bottom plate, the so-called floor panel, that for this purpose is pivoted, thereby providing an up and down movement in relation to the road surface, and which vehicle is equipped with at least one front wheel and two rear wheels, at least one of which may be driven.
2. Discussion of the Related Art
Such a device or vehicle is known from the European patent application number 0 251 136, by the applicant Yamaha Motor Co. Ltd., 2500 Shingai, Iwata-shi Shizuoka-ken, Japan.
This application is concerned with a low mounted box shaped vehicle, the so-called flat floor panel of which is pivoted and may be lowered to the road surface. During this movement, the rear side closing construction is simultaneously opened downwards, enabling a wheelchair to be driven in from behind. With the aid of a compressed air cylinder, the movement of the floor panel and the rear closing construction is accomplished by a number of bars and the rear wheel mounting. The box shaped vehicle has a front panel and left and right side-panels. The box shaped vehicle is equipped with a steerable front wheel and two driven rear wheels. The rear wheels are driven together by either an electric motor or a petrol engine.
The raising and lowering of the previously mentioned flat floor panel is made possible with the aid of a pneumatic cylinder and pump which has two possible positions, namely the lowering or external air pressure position, and several atmospheres overpressure or the maximum over pressure position. The closing rear side is a U-shaped construction that is simultaneously operated by the aforementioned pneumatic cylinder via a pivoted bar. When the air pressure in the pneumatic cylinder is released, the rear wheels move upwards in their mounting construction, simultaneously turning the U-shaped rear construction downwards onto the floor panel. This enables the wheelchair to be driven into the box-shaped vehicle from behind. Subsequently, the air pump is switched to the pneumatic cylinder, the rear wheels are pushed downwards and the U-shaped rear construction is simultaneously turned upwards behind the rear wheels of the wheelchair. Following this, the invalid's journey in the wheelchair may begin.
It has appeared from tests that the previously described familiar vehicle for taking up and transporting an invalid person in a wheelchair, also a type of wheelchair shuttle, has a great number of drawbacks. Through these drawbacks, this vehicle would appear less suitable for easy and comfortable use by a handicapped person.
In the first place, the second point of the wheel mounting construction, pivoted on the aforementioned compressed air cylinder, is connected to the vehicle's body frame. A compressed air cylinder is unsuitable for use as a suspension element as this cylinder has only two "fixed" positions: full pressure, as the vehicle's operational pressure and the external air pressure for lowering the aforementioned floor panel. In brief, a compressed air cylinder as such is not designed for use as a suspension and/or damper element, but only for effecting the mechanisms's two positions, which two positions are also fixed. Any form of comfortable suspension during the journey is therefore absent. Furthermore, the familiar vehicle has no provisions to prevent the invalid-occupied wheelchair from rolling back. Moreover, the U-shaped rear closure is turned up just above the floor panel in the drive-on position, causing an extra, serious resistance when driving onto the vehicle. This resistance has proved difficult for the invalid in his wheelchair from to overcome. Moreover, there are no provisions to prevent the wheelchair moving during the journey, which could be extremely dangerous for the invalid in the wheelchair during a sudden or emergency stop. It can now also be said that driving a wheelchair onto the floor panel, which is relatively thick, is moderately difficult for the user.